Energetics of binary iron nitrides

Effect of dopants on thermal stability and self-diffusion in iron-nitride thin films

“…• f , and atomic size for the most popular dopants used in the Fe-N system [11,[35][36][37]. It was suggested in some studies that high f and small H • f of X may result in higher activation energy for diffusing N atoms, resulting in a thermally stable phase [28,35].…”

“…% N), N atoms get dissolved interstitially into the host metal lattice [9,10]. Due to dominant Fe-Fe interactions, N atoms are weakly bonded to Fe atoms and preserve the structure and the magnetic properties of Fe [11]. Magnetic properties of interstitial Fe-N supersedes pure Fe, giving rise to interesting effects such as giant magnetic moment [12][13][14], soft magnetic properties [15,16], perpendicular magnetic anisotropy [14,17,18], etc.…”

“…Magnetic properties of interstitial Fe-N supersedes pure Fe, giving rise to interesting effects such as giant magnetic moment [12][13][14], soft magnetic properties [15,16], perpendicular magnetic anisotropy [14,17,18], etc. However, interstitial Fe-N with such a large amount of N are thermodynamically unfavorable [11], and unlike iron oxides, their enthalpy of formation ( H • f ) is at least an order of magnitude more, and even positive as in the case of α -Fe 16 N 2 ( H • f = 85 ± 47) [11]. In equilibrium, the solubility limit of interstitial N in bcc-Fe is just 0.4 at.…”

Nonmagneticγ″-FeNthin films epitaxially grown on Cu(001): Electronic structure and thermal stability

“…9,25 The resulting ratio is Fe 1.1Ϯ0.2 N. This composition is clearly different from the one ͑Fe 4.0Ϯ0.2 N͒ obtained under the same experimental conditions, but keeping the Cu͑001͒ substrate at 700 K. 9 We can conclude that the iron nitride compound grown at 300 K has a ␥Љ-FeN structure epitaxial with the Cu͑001͒ substrate with a limited in-plane dispersion with respect to the Cu atomic axis. Tessier et al 26 The FeN fcc phase can appear in two possible crystalline structures: a ZB type ͑␥Љ-FeN͒ and a sodium chloride type ͑␥ٞ-FeN͒. 12,27,28 However, the actual existence of both phases for films is still a matter of controversy.…”

Predicting New Ferromagnetic Nitrides from Electronic Structure Theory: IrFe3N and RhFe3N

“…The absolute stabilities of the MFe 3 N family of compounds was studied with respect to plausible educt phases by theoretically determining the total electronic energies of all the participating elements. [25] In addition, the nitride phase FeN which adopts the zinc blende type was included because theory indicates that this binary compound is enthalpically more stable than the elements, in accord with independent calorimetric measurements; [26] in fact, the phase designated FeN 0.91 is the most exothermic iron nitride (DH f % À50 kJ mol À1 ). Given the simple chemical reaction in Equation (1), the absolute energetic stabilities of MFe 3 N over all competing phases result as Equation (2).…”